Method for gantry angle repositioning on rotational teletherapy equipment

Area of Science:

• Medical Physics
• Radiation Oncology
• Instrumentation

Background:

• Radiation therapy requires precise alignment of the gantry angle for accurate dose delivery.
• Existing repositioning errors of +/-0.5 degrees can compromise treatment efficacy.
• The need for improved angular accuracy in radiation therapy is critical.

Purpose of the Study:

• To develop and evaluate a method for reducing gantry angle repositioning errors.
• To enhance the precision of radiation therapy delivery through improved angular accuracy.
• To decrease the time required for gantry repositioning in clinical workflows.

Main Methods:

• A laser system was mounted to the accelerator's counterweight.
• The laser beam was projected at 90 degrees to the x-ray beam axis.
• The laser served as a lever arm to magnify small angular changes (0.1 degrees) into larger distances (0.125 in.).

Main Results:

• Gantry angles can now be repositioned with an accuracy of 0.1 degrees.
• The laser indicator system effectively reduced repositioning errors.
• Routine implementation of the laser system decreased the time needed for gantry repositioning.

Conclusions:

• The laser beam indicator is an effective tool for improving gantry angle accuracy in radiation therapy.
• This method offers a practical solution to minimize undesirable repositioning errors.
• The system enhances efficiency and precision in radiation oncology procedures.